FRED joins the ESL57

Full Range Electrostatic Doublet, or FRED as it was affectionately named by Peter Walker.

I think if you have owned and appreciated the fabulous 57, at some point you also have to try the speaker that took nearly two decades to develop.

I was lucky enough to find this pair in the PFM classifieds for £250.
Insanely cheap you might think but one speaker wasn't working, though the other was fine and the pair were in good condition in other respects. Both had been to Quad for a service 7 years ago and most panels had been replaced.
With the 63, one of the most common problems is failure of the glue holding the stators to the plastic grid structure that forms the panel. The glue fails, the stators flap around and arcing occurs.
In this instance one of the old panels that hadn't been replaced had now failed.

A short email to Ron and Steve at One Thing Audio revealed that the panel could be restored to as new condition and returned within a week, for the very reasonable sum of £109.
The guys at One Thing are very helpful and have been refurbishing Quad electrostatics for many years. If you happen to have a more challenging repair, they'll service a complete set of four panels at a good discount.
This is time consuming, messy work and clearly good consistency is essential. It makes the modest prices charged all the more attractive IMO.
I can report that the refurbished panel sounds exactly like Quad panels - identical.

To complete this pair the wooden tops have been stained and oiled though there is still a little work needed to finish the job, including staining and oiling the wooden bottom cap. A new set of black stocking covers will be here (from One Thing) shortly and I'll upload some pics of the finished pair in a week or two.

In the meantime, have some ESL63 pron

Open 63 wrapped in cling film to keep out any curious passing insects....



Repaired panel ready to install.



Here you can see the link wires that join the panels. These are repeated on the back.



Rear showing HT wires running up the centre.



New panel mounted.



Dust covers and metal screen back in place - saucy 63 with her knickers at half mast...



Nearly finished.



Caps sanded and given a few coats of danish oil.




Sound later....... but tis very good indeed

 

I always seem to prefer the 57 to the 63. Very low price though.

 

wow rob, what a master piece, they are trully awesome

 

Early days, but the 57 probably edges it over a narrow band that captures most vocals - female at least. But it will only do this for one listener sitting in exactly the right spot. I'm convinced this preference is a balance and directivity issue and that what is often referred to as the achilles heel of the 57 is actually responsible for the 'magic' mid.

The 63 has unquestionably cleaner and has more dynamic bass.
It also at least hints at some real low bass - the 57 has none.
You can get useable output down to 35Hz on the 63 with a little help from the room.

You do indeed, but you cant blow up a Quad 405 with electrostatics
I had the SL10 in use with a MM cartridge fitted and didn't fancy dismantling the Quad rack to swap phono cards.
The Cyrus drives them perfectly though.

 

Very nice, Rob

Not much risk of blowing anything up with 63s - they are very benign load:

 

Hi Martin,

Yes, and it gets easier to drive the harder you drive it.

The dynamic impedance swings are surely large enough in the bass to make some valve amplifiers sound a bit strange.
A typical valve amp seeing level dependent impedance swings from 6 to 38 Ohms below 100 Hz is going to modulate the response.

Look at that distortion result - good amplifier class distortion above 150Hz, ie well below 0.1%.
I think it hits around 0.03% in the mid and top IIRC.

 

That's what the graph shows, and the review I lifted it from noted their results were limited by the test oscillator available. Note at the extreme bass end it barely reaches1% distortion at 20Hz - still not many dynamic speakers can come close to that.

I'd love a pair of these or the 989s.

One thing I would be interested in playing with is internal the 220uF coupling cap in (in parallel with 1R5 i think) It's a (now-ancient) bipolar electrolytic, and if a modern film type could be made to fit... I'd certainly try it

 

I have some fresh 200uf electros on order and a pair of 20uf Solen films, the parallel pair giving the required 220uf.

The cap/resistor combo looks like it would subtly tilt the response, lifting the mid and top a tad relative the the bass which would be attenuated by the 1R5 series resistor.
Unless I read this wrong.

 

That's it, around 480-500Hz. Will be interested to hear how this goes...

 

Hello Felix,

I have a soft spot for the 989's a very under rated speaker.

 

Very nice Rob.

 

Me too - also the 2905s, although the brace added on those actually undoes a certain amount of fore-aft flex PJW actually intended in the 63s (it mitigates excess acoustic output c. 60-90Hz arising from the primary bass membrane resonance. You cannot ever accuse PJW of not addressing specifications...)

O/T - but what I always find fascinating is that Quad ESLs - all of them - often sound dull when auditioned directly after almost any other speaker. Then, after 2-3minutes suddenly I don't care any more and the rest of the night is wasted on listening, really listening, to music into the early hours

IOW lack of distortion is its own reward. And with Quads you are also unlikely to annoy the neighbours. A brilliant solution!

 

PJW commented at the time that certain people, thinking they understood the design, mounted the speaker into rigid frames.
This he said made the bass go 'woof woof' for precisely the reason Martin states.

The only thing i don't quite get is his decision to make the speaker a short floorstander. They sound much better when raised, certainly in small rooms though perhaps this is less of an issue in a larger room and a more distant listening position.
Of course Quad started to supply a frame stand about two years into production.

 

I think the point of the floor 'mount' was to exploit the floor reflection in support of the bottom couple of octaves - it's a speaker only designed to be measured/listened to at least 2M+ away. As I see it - that epitomises a basic cognitive problem with all the Quad ESls: they can fully drive small rooms, but you know it really wants to sounds best in *huge* room volumes free of reflection... bang fizzzz.


Anyway let us not forget it was designed and perfected over decades by a man who played woodwind for pleasure in choirs/ orchestrae most of his life - the most difficult of timbres to reproduce correctly

 

I used to run my ESL57s with a Cyrus One. No problems at all, although
the Quad 306 I replaced it with sounded vastly better.



As for the RC network in the ESL63's input: there are old reports on
the internet of enthousiasts modifying the RC to their preference.
Some ended with more C, others with less.

I also believe that SME's ARA had moved the RC network entirely
out of the speakers, and replaced the Cs with huge banks of film
caps.

I intended to do the same, but in the end I didn't bother (surgery on ESLs
is not my definition of a good time). However, I once did add 20uF
polypropylenes in parallel to the existing 220uFs. Noticed no difference.

 

Hi Werner,

The 306 is my favourite of the Quad power amps.
A serviced 306, with the input sensitivity reduced and slightly uprated PSU caps is superb. Nothing else need be done to it IMO. You can add a little rail decoupling around the op amp but in this design, which doesn't have the op amp providing first stage gain, it made no difference.

 

Sadly I sold my whole Quad stack to fund a DIY project.

Which ended up in the bin.

 

34,306,FM4 are all around £150 a pop these days and excellent value.

Buy another set

 

Now that the 63s have been in place for a couple of weeks I've started to form some firm opinions of them, especially relative the the 57.

The first thing I'd say is don't worry too much about wall distance, and that like the 57 they do work well in smaller rooms with a little care. That doesn't mean you can shove them against a rear wall or into corners, but about 1m out into the room and angled inwards slightly is fine.
It is often said that Quad ESLs need a large room and lots of free space, and while that might help get ultimate performance in some areas, ESL don't actually like driving large rooms IMO. In a smaller room and a more near-field listening position the often mentioned maximum SPL restrictions are far less of a concern. The balance is also lighter and fresher on both models in near-field.

Don't sit a 63 directly onto the floor in a small/medium room.
They sound dull and rolled-off, a trait exaggerated by boosted upper bass in that position.
So get them up high - I'd say get the centre of the speaker just a touch above ear level.
In my room that gives a nice even response extending out past 20k.

On first hearing 57s I was quite shocked at just how good they were. Wonderfully intimate on vocals with true hear-through clarity and transparency. Not perfect though, and there is no low bass (I mean none), plus there is some thickening and 'thrumminess' on deep male voices for example that detracts from an otherwise stunning result.
Dynamics are quick and sharp though there is little sense of physical impact, but that is true for many planar designs.
They remain one of the best ways to get direct coupled to the performance IMO, so long as the limitations are respected and accommodated.

The 63 makes for interesting comparison.
The first thing noticed (when lifted on stands) is that the slightly tailored 'niceness' of the 57 is replaced with a more honest balance. 57s have a classic BBC dip response and the 63 is flatter - more like a studio monitor in that regard.
It also (mostly) lacks the rising extreme top end of the 57* and I believe this is why some claim the 63 to be less magical. Boosted high end relative to the presence band subjectively enhances delicacy, detail and sweetness. The 63 is flatter so on first listen can appear lacking in these areas but you soon adjust to the new balance and realise that everything is there. I'm also firmly of the view that some of that 57 magic is directly related to the treble dispersion which is extremely tight. You really do have to shuffle around and 'lock-in' to the speaker and I think that this enhances the feeling that you're coupled to the music. The 63 doesn't do this to anything like the same degree but is no worse for it IMO.

One surprise was that the 63 will go a good bit lower and happily deliver 40Hz in room at good level. Bass, and especially upper bass is considerably cleaner than the 57 and it'll play louder with more impact.

Another difference between the two Quads is front-back soundstaging.
The 57 gives a wide presentation but one that's obviously truncated in terms of depth - layering if you like. On suitable recordings the 63 stretches the soundstage concertina style, which can be impressive on good, natural, simple recordings and very illuminating on complex studio multitrack stuff. For example, you can often clearly hear the different bandwidths, noise and acoustic characteristics of different elements within the mix.
This is quite new to me, certainly this level of forensic dissection of a mix and I'm sure it subconsciously pokes fun at the remnants of latent flat-earthism that lurk within

Which is best?
Well I'd say that depends on how you listen.
If you listen at low volume, perhaps mostly in the evening to simple, good quality recordings and speech, I'd say the 57 edges it.
if you have wider music tastes, like to wind up the volume now and then, and want better absolute fidelity for more of the time, the 63 is the better choice.


* The 57 displays a rising response above 10kHz when used with a good SS amplifier.
No mystery here. Impedance at HF falls to around 1.3 Ohms and so response will naturally flatten when driven by most valve amplifiers, with higher output impedance.
So a 57 driven today by a super tight SS amp is probably not quite what the Master intended in terms of balance.